Singed migration: Birds detour around wildfire smoke, study finds
New research published in the journal Ecology is the first to use GPS-tracking data to look into the effects of wildfire smoke on bird migrations. But researchers say the study was a lucky accident.
"It was really a stroke of luck, a lot of things had to happen, all at the right time, in order for us to see this," said Cory Overton, a wildlife biologist with the U.S. Geological Survey and lead author of the paper.
He and a group of researchers had been tracking GPS-tagged tule geese—a large, gray bird that nests in southern Alaska and winters in central California marshes—as part of a migration study.
Then, in September 2020, Overton said they noticed one goose hundreds of miles off course, in the Idaho panhandle.
"These birds are so focused on one particular area in Central Oregon that even a few 100 miles off course is pretty unusual," he said.
That wasn't the only migratory deviation. Three birds migrating over the Pacific Ocean stopped for a few days and floated before moving back inland. And landward birds rose to 13,000 feet in the air, when tule geese usually stay relatively close to the ground when flying.
When researchers went looking for a potential cause, the geese's strange movements lined up with areas of dense wildfire smoke. Overton said they worked with the National Oceanic and Atmospheric Administration and its new tool to predict three-dimensional distribution of smoke.
"It really helped us kind of narrow in that these birds were encountering smoke and it was making them do pretty much everything that they could do to try and avoid it," he said, "They could go around it, they could go over it, or they could sit and wait it out. And they pretty much did all three."
Fortunately, the tagged tule geese survived, but not before using much more energy than they would usually need during their southward migration. Overton said smaller birds, especially ones that don't have the ability to land on water, may not have survived the smoky journey.
"I think the margin of error for a flycatcher, for example, is far slimmer than it would be for a tule goose," he said. "What our data shows is that these birds can be affected, they can be affected in multiple ways. And some species are going to be more strongly impacted than others."
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